Refrigeration apparatus and method



May 7, 1963 R. M. HENDERSON REFRIGERATION APPARATUS AND METHOD 2 Sheets-Sheet 1 Original Filed Feb. 1, 1956 INVENTOR. RAY M. HENDERSON ATTORNEYS y 1963 R. M- HENDERSON 3,088,293

REFRIGERATION APPARATUS AND METHOD Original Filed Feb. 1, 1956 2 Sheets-Sheet 2 ATTORNEYS i [N V EN TOR.

MAM

United States Patent 3,088,293 REFRIGERATION APPARATUS AND METHOD Ray M. Henderson, 139 E. Ridgewood Court, San Antonio, Tex. Continuation of application Ser. No. 562,826, Feb. 1, 1956 This application Sept. 11, 1961, Ser- No. 137,362 so Claims. c1. 62-197) This invention relates to refrigeration apparatus and method and more particularly to an apparatus and method of controlling flow of refrigerant particularly useful with heat pumps and the heating cycle of reverse cycle of reverse cycle systems. In one important aspect it relates to valves used in the apparatus.

This application is a continuation of my copending application Serial No. 562,826 filed February 1, 1956, now forfeited, which application is a continuation-in-part of my application Serial No. 397,309, now Patent No. 2,807,145 filed December 10, 1953.

In the process of evaporation of liquid refrigerant in an evaporator of a conventional refrigeration system, it is obvious for well-known reasons that the level of the liquid in the evaporator must be controlled. Among the reasons for such control is the necessity of control and regulation of super heat of the boiling refrigerant, efficient utilization of heat exchange surface, and prevention of unevaporated liquid refrigerant from passing through the evaporator to the compressor.

There are numerous well-known means and methods of regulating the flow of liquid into refrigeration evaporators such as expansion valves of numerous kinds, float valves and other means of restricting the flow of liquid and causing a pressure drop at the point where the liquid enters the evaporator. In most of these devices, the refrigerant is passed through a rather small orifice to thereby cause a drop in pressure between the supply source of the liquid and the evaporator. This pressure drop becomes necessary in the conventional refrigerant evaporation process because of the high pressure of liquid refrigerant that has been condensed with the use of conventional air or water cooled condensers. Also because of the high pressure on the liquid, a comparatively small orifice or passageway is necessary for accurate control of the flow of this liquid as it passes into the evaporator from its source of supply.

In heat pumps, reverse cycle systems and hot gas defrosting systems, especially those applied to low pressure refrigeration, the pressure conditions may be entirely different. In defrosting systems, for instance, wherein hot gas is transmitted to the regular refrigeration evaporator for defrosting, condensation of the refrigerant takes place in the evaporator, the temperature of which is necessarily low. It is therefore obvious that the temperature of the liquid, thus condensed in the defrosting operation, will be much lower than that of liquid refrigerant which has been condensed by normal processes, and for the reason that the pressure of the refrigerant is reduced proportionately to reduction in temperature, the pressure of this liquid as it is condensed and returned for re-evaporation is usually very low and entirely inadequate to force sufficient liquid through a conventional flow-restricting device, such as an expansion valve, to supply enough liquid to the evaporator for etficient operation in the process of absorbing heat for defrosting.

It has been found in the operation of reverse cycle defrosting systems wherein the liquid from the receiver is metered through an expansion valve to a second evaporator or to the condenser, to thereby convert the condenser into a second evaporator, that the performance of the second evaporator is very inefficient because the supply of liquid was not adequate to abosrb sufficient heat for defrosting.

I have discovered that How of liquid refrigerant may be regulated by controlling the pressure Within the receiver to maintain a pressure in the receiver just suflicient to feed liquid refrigerant into the second evaporator at the desired rate. One system of controlling receiver pressure is shown in my copending application Serial No. 499,912, now Patent No. 2,904,967. Another system of controlling receiver pressure is shown in my copending application Serial No. 284,730, now Patent No. 2,763,130 and copending applicational Serial No. 397,309, now Patent No. 2,807,145, the latter of which is a continuation-in-part of said copending application Serial No. 562,826.

It is an object of this invention to provide a refrigeration system and method of operating a refrigeration system in which the liquid level in the evaporator is regulated without the large pressure drop usually associated with evaporator control.

Another object of this invention is to provide in a refrigeration system a method and means for transmitting liquid from the receiver to the evaporator of the system and controlling and regulating the amount of liquid so transmitted in response to a condition of the refrigerant leaving the evaporator.

Another object is to provide in a refrigeration system a means and method of regulating and controlling the superheat of an expanding refrigerant in a refrigeration evaporator without a large pressure drop between the source of liquid supply and the evaporator.

Another object is to provide a method and means to control the flow of liquid refrigerant from a liquid receiver to an evaporator of a refrigeration system by controlling the difierence of gas pressure therebetween in response to a condition of the refrigerant leaving the evaporator.

A still further object is to provide in refrigeration apparatus a means and method for releasing gas pressure from one portion of the apparatus to another in response to the temperature or pressure of the refrigerant on one side of said means so to cause pressure on the opposite side to be reelased proportionately to changes in said temperature or pressure to thereby regulate and control the pressure difference between one side of the means and the other.

Another object is to provide means in a reverse cycle refrigeration system to release pressure from the receiver of said system at the beginning of the reverse cycle to thereby reduce the receiver pressure below the pressure in the evaporator being defrosted and thus cause the liquid which is condensed as a result of said reverse cycle operation to return to the receiver and to continue to release pressure from the receiver proportionately to changes in pressure or temperature in another part of the system to regulate flow of liquid refrigerant from the receiver.

Another object of this invention is to provide valve means particularly adapted to the regulation and control of the refrigerant pressure in the receiver of a refrigeration system during reverse cycle operation thereof in response to a condition of the refrigerant leaving the evaporator.

Yet another object is to provide a novel pressure differential valve for aiding reverse cycle or defrosting operations of a refrigeration system which is operable in response to changes in the temperature or pressure of the refrigerant leaving the evaporator to control the pressure at the inlet of the evaporator to thereby control the amount of liquid transmitted thereto through said inlet.

Other objects, features, and advantages of my invention will become apparent from the following description taken in connection with the accompanying drawings in which like reference numerals indicate like parts and in which:

FIG. 1 is a schematic view of a reverse cycle refrigeration system illustrating my invention;

FIG. 2 is a sectional view of the pressure regulating valve shown in FIG. 1 whereby the novel results of my invention are obtained;

FIG. 3 is a schematic view of another form of reverse cycle refrigeration system illustrating my invention; and

FIG. 4- is a sectional view of the pressure regulating valve shown in FIG. 3.

The condensing unit shown in FIG. 1 is of the water cooled type, but it could be of the air cooled type as illustrated in FIG. 3 or a combination of both without materially affecting the adaptions and functions of this inven tion and in view of this, the scope of my invention is not to be limited to any particular type of system.

In the conventional refrigeration system shown in FIG. 1 there is a compressor P, a condenser C, a receiver R, an evaporator E, an expansion valve X, and the usual connections therebetween, the functional operation of which is well known and understood. A water valve WV regulates the rate of supply of Water to the condenser.

In combination with this conventional refrigeration system is shown a reverse cycle heating system designed for defrosting evaporator E, including a reversing valve RV, an expansion valve bypass including a check valve CV, a heat exchanger HX, a liquid diverting valve DV, a reverse acting water valve WV a liquid connection known as a dip tube between the receiver and the condenser C, a bypass conduit connection 11 between the receiver and the conduit or condenser line CL which connects the condenser and the compressor in which is incorporated a pressure regulating valve PR, forming an important feature of my invention.

In this defrosting system, the reversing valve RV is of the conventional type and is operable by various means, preferably automatic, to reverse the flow of refrigerant in most parts of the system to thereby cause hot gas from the high side 12 of the compressor to be diverted through the suction line SL to the evaporator E where it will function as a heating medium to melt the frost which has accumulated during the refrigeration cycle of the system. The absorption of heat from this gas during this defrosting process will cause the gas to condense in the evaporator and become a liquid, which will flow by gravity to the bottom of the evaporator where it can pass through the check valve CV into the liquid line LL when the pressure conditions permit this valve to open. Simultaneously with this diversion of hot gas to the evaporator, the condenser line CL is connected through the reversing valve RV to the low side 13 of the compressor. This connection of the condenser to the low side will cause a pressure drop in the condenser and thereby convert the condenser into an evaporator. In this manner, the regular refrigeration evaporator Will become a condenser during the defrosting operation and the regular condenser will become an evaporator, which will sometimes be referred to in this description and claims as a second evaporator. On such reverse cycle, the receiver actually functions as an evaporator since gaseous refrigerant is removed therefrom and therefore, the receiver is sometimes referred to as first evaporator means in the claims. It will be understood that a separate second evaporator, not used during the refrigeration cycle, might be used during the heating cycle if desired and condenser C cut out of the circuit.

When during defrosting the pressure in the second evaporator is reduced below the pressure in the receiver R, liquid refrigerant will flow from the receiver R through the dip tube 10 to the second evaporator and will be evaporated by the usual boiling process to absorb heat from the water or air, whichever the case may be, which is supplied to the condenser as a heat bearing agent for heat exchange with the refrigerant.

Pressure regulating means is provided to control release of gaseous refrigerant from receiver R and first releases excess pressure from the receiver to permit normal circulation of refrigerant to commence immediately after the system is placed on reverse cycle. The pressure regulating means then regulates the rate of flow of liquid refrigerant into the second evaporator in accordance with a condition of the refrigerant leaving the second evaporator. This release of refrigerant may be through a valved bypass lime directly interconnecting the receiver and compressor or it may be through the condenser by the use of a dip tube in the receiver whose height may be controlled as in my copending application SerialjNo. 499,912.

My improved pressure regulating valve PR, as shown in detail in FIG. 2, is provided with a body 14 having a bore 15; Communicating with this bore is the condenser line CL, already referred to, and opposite thereto. This bore is also connected to the reversing valve RV by a conduit 16. In the lower part of the bore 15 is an adjustable valve seat 17 which is threaded into the body and adjustment is made possible by a stem 18 connected thereto and extending out of the lower end of the valve body, this stem being suitably packed, as shown, so that leakage cannot occur. Below the valve seat 17 there is provided a chamber 19 which has connected thereto the conduit 11 already referred to and connected to the top of the receiver R above any liquid line. Cooperating with the adjustable valve seat 17 is a check valve disc 20 for controlling the flow of refrigerant vapor past the valve seat 17 from the receiver to the bore 15 above the valve seat. The check valve disc 20 is acted'upon by a pressure spring 21 interposed between the disc and the lower end of a plunger stem 22, which plunger stem extends upwardly through a perforated guide 23 at the top of the bore 15 and into a cap 24. A pressure responsive member such as a bellows 25 is positioned in the cap with its free end connected to the top or free end of the plunger stem and the other end of the plunger being connected to a closure plate 26 for the cap. The pressure responsive member 25 is exposed on one side to suction pressure through guide 23 and its movement is therefore influenced by the pressure of the gaseous refrigerant generated by condenser C.

The interior of the cap outside the bellows is connected by a capillary tube 27 to the bulb 28 attached to the con-v denser line CL as shown in FIG. 1. The movement of the plunger is controlled by the bellows 25 and the pressure in the cap and the movement of the plunger is further under the control of a compensating spring 29, said spring being interposed between the perforated guide 23 and a washer 30, welded or otherwise secured on the lower end of the plunger stem. Valve pressure spring 21 bears against the underside of washer 30. An open top cage 31 encloses spring 2-1 and washer 30. The bottom of the cage is secured to valve member 20. The top of the cage has an inturned flange 32 overlying washer 30. As soon as plunger 22 moves upward a suflicient distance to engage washer 30 and flange 32, the valve member 20 is limited against further movement away from plunger 22 and further upward movement of plunger 22 will unseat valve member 26.

Again referring to FIG. 1, it will be noted that the reversing valve RV is associated with the suction line SL between the evaporator and the compressor P and the liquid line LL coming from the evaporator is connected to the diverting valve DV which has a conduit 33 connected to the coil 34 of the heat exchanger HX, which in turn is connected by a conduit 35 to the bottom of the receiver. Another line 36 from the diverting valve bypasses the heat exchanger. The water valves WV and WV control the flow of water from the water supply line 37 to the chamber surrounding the heat exchanger and through the condenser to the water discharge line 38. These water valves will be controlled by pressure in the condenser line CL, such being accomplished by conduits 39 and 40 leading to the control chambers of the water valves. It will be noted that the water line between the heat exchanger HX and the water supply 37 is divided into two lines 41 and 42, with the water valve WV in the line 41 and the water valve WV in the line 42. The chamber of the heat exchanger is connected to a usual coil in the condenser, not shown, by a conduit 43.

During the refrigeration cycle hot refrigerant gases in line CL will heat bulb 28 and the pressure within cap 24 will be such as to maintain the plunger 22 in its full down position. The valve disc 20 of the pressure regulating valve PR will remain closed and inoperative and such will have no effect in the system. This condition occurs because receiver pressure is transmitted to the lower side of disc 20 from the receiver R through conduit 11 and condenser pressure is transmitted to the top side of said disc by the direct connection to the condenser through the line CL. As a result, the high side of the compressor is efiective on the top of the disc 29 and it is held seated.

When defrosting takes place by an operation of the reversing valve RV, generally automatically, the pressure in the condenserC will immediately be reduced by a pumping of gas therefrom by the low side of the cornpressor. The suction pressure of the condenser which now becomes a second evaporator, as previously indicated, will also immediately be reduced and assume a value below the pressure in the receiver. This causes the check valve disc 20 to be unseated and gas from the receiver is released into the condenser line CL, now connected to the low side of the compressor. The receiver pressure is consequently reduced, but controlled and limited by the functioning of the valve PR.

Thus, during the initial stage of defrosting when plunger 22 is in its full down position and the receiver pressure is necessarily greater than the suction pressure of the condenser acting as a second evaporator, the difference in pressure between the receiver and the second evaporator will become equal to the pressure exerted by the spring 21 on the check valve disc.

From experience it has been determined that the most eificient operation of a condenser used as an evaporator is obtained by a flooded condition or by maintaining the liquid level in the condenser as near the top as possible without flooding over into the suction line and the compressor. This condition is maintained throughout the defrosting operation by the functioning of this valve.

It is common practice to lift liquid by providing adequate pressure behind the liquid to be lifted. In this operation, pressure of sufiicient force to lift the liquid refrigerant from the receiver to the desired height in the second evaporator is maintained above the liquid in the receiver, and it is a function of valve PR to so regulate this pressure that there will be suificient pressure exerted on this liquid to lift it to the required height in the evaporator and to control this pressure to the extent that the liquid will not be forced out of the top of the evaporator into the compressor. It is another function of this valve to regulate the liquid level in proportion to the usable heat exchange surface of the evaporator to thereby control the superheated condition of the refrigerant during the evaporating process.

With respect to this, the spring 21 is important as it is of such compressive strength as to hold sufficient pressure in the receiver over the amount of pressure on top of the liquid in the condenser-evaporator, with stem 22 in full down position, to lift the liquid from the receiver to at least the point at which the bulb 28 is fastened in heat exchange relation with the evaporator suction or the point at which it is desired to stop the rise of liquid in the evaporator and maintain the liquid level. 'The power substance or the composition with which the bulb is charged is of a substance having a low boiling point, preferably the same refrigerant as used in the system. When the boiling liquid in the evaporator reaches the point of heat exchange relation with the bulb 28, heat is absorbed from the refrigerant in the bulb which will cause the temperature to be reduced and thereby reduce the pressure in the cap 24 which is exerted against the bellows 25. This reduction of pressure in the cap 24 will permit the pressure of the refrigerant, which is exerted against the inside of the bellows, to extend the bellows to thereby move the stem 22 upwardly to thereby reduce the pressure of the spring 21 against the top of the valve disc 20, which in turn will reduce the amount of pressure difference between the receiver pressure and the evaporator suction pressure. This reduction in pressure difierence will cause the height of the liquid level in the second evaporator to be reduced and heat will no longer be taken from the bulb by refrigerant evaporating in line CL adjacent the bulb. The pressure in the power element will then increase by absorption of heat from the superheated gas in the suction line to again exert pressure on the bellows which is greater than the suction pressure, to thereby cause movement of the stem 22 downwardly and increase the pressure difference across valve 20 to cause the liquid level to rise in the condenser C which is serving as the second evaporator. In many instances pressure conditions will be such that, after excess pressure is released from the receiver and the pressure in bulb 28 reduced by giving off heat to the system refrigerant, the valve will regulate pressure with the cage flange 32 and washer 30 in abutting relations p. The chilling and heating action of the system refrigerant on bulb 28 will soon reach an equilibrium condition and valve 20 will maintain a diflerential which will hold the frost line at or just below bulb 28.

By this action it is apparent that the boiling liquid in the condenser C which is serving as the second evaporator will be limited in its passage through the condenser C serving as the second evaporator by the placement of the bulb 23, and that the boiling liquid will be held at the desired level in the condenser by regulation of the pressure difference between the receiver and the suction side of the condenser C serving as the second evaporator.

It is obvious that in various condensing units and their application the pressure difference required to lift the liquid to the proper height in the condenser acting as a second evaporator will vary, and therefore a variation of the spring pressure on the check valve disc will be necessary. To accomplish this variation of spring pressure the valve is provided with the adjustable seat 17. This valve seat may be raised or lowered to a limited extent. By moving the seat upwardly, the spring pressure of spring 21 will be increased to thereby increase the pressure difference, and by downward adjustment the spring pressure and pressure difference will be decreased. This adjustment may also be used for adjusting the liquid level proportionately to the amount of usable heat exchange surface of the evaporator to thereby adjust and regulate the superheat of the expanded refrigerant.

As previously stated, an object of this invention is to control the liquid level or the supply of liquid to an evaporator by controlling or regulating the difference of pressure between one side of the evaporator and the other. This regulation of pressure is accomplished by the adjustment of spring pressure against the top of the valve disc of my improved pressure regulative valve PR. Both manual and thermostatic or automatic adjustment of the spring pressure has been provided, and therefore the improved valve may be adjusted manually to control the liquid level without the use or operation of the thermostatic means. Although manual adjustment might .to regulate suction pressure at this time.

3,oss,293

requiremore time and trouble, satisfactory results may be obtained.

In addition to the above described refrigerant evaporation regulating means, the water control system including two Water control valves WV and WV and a heat exchanger HX are employed, as shown in FIG. 1. This water control system is illustrated and described in detail in my co-pending application Serial No. 397,309 referred to above and therefore need not be further described or discussed herein.

Referringnow to FIGS. 3 and 4 this invention is illustrated in a system having an air cooled condenser C and heat exchanger HX and the liquid level in the condenser is controlled during the heating cycle without the use of bulb 28 by a pressure regulating valve PR Referring particularly to FIG. 4 of the valve PR is interposed in the conduit between the condenser C and compressor P and permits free flow of refrigerant therethrough from inlet passageway 43 to outlet passageway 44. Bypass conduit 11 communicated with the inlet 43 and outlet 44 through passageway 45. Fluid flow through passageway 45 is controlled by a valve seat 46 in passageway 45 and a cooperating valve member 47. Valve member 47 is free floating in passageway 45 and is guided in its movement to and from seated position by :guide 48 which slidably engages the wall of passageway 45.

A plunger 49 is reciprocally mounted in the valve body 55 and biases the valve 47 toward its seat. A spring 50 is interposed between valve member 47 and plunger 49 and permits valve 47 to leave its seat when the system is placed on reverse cycle operation to relieve the excess pressure in receiver R.

The plunger 49 is secured to the free end 51 of bellows 52 and reciprocates with changes in suction pressure in line CL to vary the force exerted by spring 50. In this manner the differential between-suction pressure and receiver pressure is varied with changes in suction pressure. Suction pressure reaches the inside of bellows 52 through plunger guide 53.

Adjustment of the force exerted by spring 50 is provided by a biasing means such as spring 54 mounted externally of valve body 55 in a cage 56. Cage 56 is secured to body 55 by through bolts 57 and held in spaced relationship therewith by cylindrical spacer 58 surrounding bellows 52. The force of spring 54 is exerted on the bellows throughan end plate 59 which engages a stem 60 carried by bellows 52 and extending into cage 56. The force exerted by spring 54 may be selectively varied by rotating adjusting screw 61 which is threadedly carried in top end plate 62 for spring 54. Screw 61 has a shoulder 63 which engages thrust plate 64 and holds the screw 61 against longitudinal movement by the force of spring 54. Screw 61 also provides a stop for limiting expansion of the bellows during the cooling cycle.

During the cooling cycle of the system valve member 47 remains seated as the pressure in line CL is always greater than receiver pressure. As soon as the cycle of operation is reversed, hot gas condensing in evaporator E reduces evaporator pressure. Compressor P is also acting to reduce pressure in line CL. Under the influence of these two factors valve 47 will unseat and gas from receiver R will be bypassed until excess pressure is removed permitting check valve CV to unseat and normal circulation to begin. Bellows 52 will begin to function The force exerted by spring 54 will be adjusted to maintain a suction pressure which will maintain a desired liquid level in condenser C now functioning as a second evaporator. Suction pressure and the liquid level in condenser-evaporator C are directly related and an increase in the amount of liquid in condenser-evaporator C will cause an increase in suction pressure 'Which will flex bellows 52 and reduce the force tending to hold valve member 47 on its seat. Valve member 47 will unseat and bleed off pres sure from the receiver R which will permit the liquid level in 'condenserevaporator C to fall. As this liquid level falls, suction pressure reduces and bellows 52 contracts and the force tending to seat valve member 47 increases and seats the valve member to prevent furtherreduction of receiver pressure. 7

Heater HX continuously provides suflicient heat to vaporize a small amount of refrigerant and provide more pressure in receiver R than necessary to support the desired level of refrigerant in condenser-evaporator C It will be understood that this heat could be provided by directing some of the condenser air over the receive R or by any other desired means. In some instances it may be found that the system will develop sufficient pressure without special provisions for heat and if so heater HX may be omitted altogether.

While in both of the systems illustrated a single valve both relieves excess pressure in receiver R at the beginning of the heating cycle and thereafter regulatesthe differential between suction and receiver pressure it will be understood that these two functions might be accomplished by separate valves.

It will further be understood that relief of receiver pressure in response to a condition of the gaseous refrigerant generated in condenser-evaporator C may be through the condenser by utilizing the automatic dip tube shown in my application Serial No. 499,912 with plunger 22 or 49 connected to the free end of the dip tube bellows.

From the above it will be seen that all the objects of my invention have been accomplished. There has been provided a means and method for regulating flow of liquid refrigerant to the second evaporator during the heating cycle in response to a condition of the gaseous refrigerant generated by the second evaporator as well as novel valve means for employment in the system. 7

From the foregoing it will be seen that this invention is one Well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus and method.

It will be understood that certain features and subcombinations are of utility and may be employed Without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

What is claimed is:

l. A refrigeration system comprising, a compressor for circulating a refrigerant in the system, a condenser connected to the high side of the compressor for liquifying gas fed to the condenser from the compressor, a receiver connected to the condenser and storing liquified refrigerant from the condenser, an evaporator interconnecting the receiver and low side of the compressor and evaporating liquid refrigerant fed thereto from the receiver, means for reversing the flow of refrigerant in the system whereby to convert the condenser into a second evaporator, means for removing gaseous refrigerant from the top of the receiver to regulate the differential between receiver pressure and suction pressure to thereby regulate the rate of transfer of liquid refrigerant to the second evaporator during reverse cycle operation, and means for controlling the rate of removal of gas from the receiver in response to a condition of the gas generated by the second evaporator, said last mentioned means varying said differential to maintain a predetermined liquid level in the second evaporator.

2. A refrigeration system comprising, a compressor for circulating refrigerant in the system, a condenser connected to the high side of the compressor for liquifying gas fed to the condenser from the compressor, a receiver connected to the condenser and storing liquid refrigerant from the condenser, an evaporator interconnecting the receiver and low side of the compressor and evaporating liquid refrigerant fed thereto from the re ceiver, means for reversing the flow of refrigerant in the system whereby to convert the condenser to a second evaporator, means including bypass means interconnecting the receiver and low side of the compressor and bypassing the second evaporator, and valve means controlling tlow through the bypass means, said valve means responsive to a condition of the refrigerant for varying the differential between receiver pressure and suction pressure to control the rate of transfer of liquid refrigerant from the receiver to the second evaporator during reverse cycle operation and thereby control the liquid level in the second evaporator.

3. A refrigeration system comprising, a compressor for circulating refrigerant within the system, a condenser connected to the high side of the compressor for liquifying gas fed to the condenser from the compressor, a receiver connected to the condenser and storing liquid refrigerant from the condenser, an evaporator interconnecting the receiver and low side of the compressor and evaporating liquid refrigerant fed thereto from the receiver, means for reversing the flow of refrigerant in the system whereby to convert the condenser to a second evaporator, means including bypass means interconnecting the receiver and low side of the compressor and bypassing the second evaporator, and valve means controlling flow through the bypass means and including manually adjustable means for providing a selected differential between receiver pressure and suction pressure, said valve means responsive to a condition of the refrigerant for varying said manually selected differential to control the rate of transfer of liquid refrigerant from the receiver to the second evaporator during reverse cycle operation and thereby control the liquid level in the second evaporator.

4. In a reverse cycle refrigeration system having a compressor with its low side connected to a refrigeration evaporator through a suction line and its high side connected to said evaporator through a receiver and a liquid line during the cooling cycle, means providing for reverse cycle operation of the system to reverse flow of refrigerant in the system and heat the evaporator, means interconnecting the receiver and the low side of the compressor during reverse cycle operation including a second evaporator for generating hot gas from liquid supplied to the second evaporator from the receiver to heat the refrigeration evaporator, bypass means interconnecting the receiver and the low side of the compressor during reverse cycle operation and bypassing the second evaporator, and valve means controlling flow through the bypass means, said valve means responsive to a condition of the refrigerant for varying the differential between receiver pressure and suction pressure to control the rate of transfer of liquid refrigerant from the receiver to the second evaporator during reverse cycle operations.

5. In a reverse cycle refrigeration system having a compressor with its low side connected to a refrigeration evaporator through a suction line and its high side connected to said evaporator through a receiver and liquid line during the cooling cycle, means providing for reverse cycle operation of the system to reverse flow of refrigerant in the system and heat the evaporator, means interconnecting the receiver and the low side of the compres sor during reverse cycle operation including a condenser serving as a second evaporator for generating hot gas from liquid supplied to the second evaporator from the receiver to heat the refrigeration evaporator, bypass means interconnecting the receiver and low side of the compressor during reverse cycle operation and bypassing the second evaporator, and valve means controlling flow through the bypass means, said valve means including adjustable means for providing a selected difierential between receiver pressure and suction pressure, said valve means responsive to a condition of the refrigerant for varying said selected differential to control the rate of transfer of liquid refrigerant from the receiver to the second evaporator during reverse cycle operation.

6. A reverse cycle refrigeration system comprising a compressor for circulating refrigerant in the system, a condenser connected to the high side of the compressor for liquifying gas fed to the condenser from the compressor, a receiver connected to the condenser and storing liquid refrigerant from the condenser, an evaporator interconnecting the receiver and low side of the compressor and evaporating liquid refrigerant fed thereto from the receiver to cool the evaporator, means providing for reverse cycle operation of at least a portion of the system to heat the evaporator, a condenser serving as a second evaporator interconnecting the receiver with the low side of the compressor during reverse cycle operation and generating hot gas from liquid supplied to the second evaporator from the receiver to heat the refrigeration evaporotor, bypass means interconnecting the receiver and low side of the compressor and bypassing the second evaporator during reverse cycle operation, and valve means controlling flow through the bypass means and releasing excess pressure from the receiver upon switching cycles from cooling to heating of the refrigeration evaporator and after excess receiver pressure has been released regulating the differential between receiver pressure and suction pressure in response to a condition of the gaseous refrigerant generated by the second evaporator to control the rate of transfer of liquid refrigerant from the receiver to the second evaporator during reverse cycle operations.

7. The system of claim 6 wherein a single valve member and valve seat control flow through the bypass and both relieve excess pressure and regulate said ditferential during the operation of the heating cycle.

8. The system of claim 6 wherein the differential between receiver pressure and suction pressure is regulated in accordance with changes in suction pressure.

9. The system of claim 6 wherein the differential between receiver pressure and suction pressure is regulated in accordance with changes in the level of boiling liquid refrigerant in the second evaporator.

10. The system of claim 6 wherein the difierential between receiver pressure and suction pressure is regulated in accordance with changes in temperature of the gaseous refrigerant generated by the second evaporator.

11. A refrigeration system comprising a compressor for circulating refrigerant in the system, a condenser connected to the high side of the compressor for liquifying gas fed to the condenser from the compressor, a receiver connected to the condenser and storing liquid refrigerant from the condenser, an evaporator connected to the receiver and evaporating liquid refrigerant fed thereto from the receiver, a first conduit connecting the evaporator with the suction side of the compressor, means for effecting reverse cycle operation of the system whereby to convert said condenser into a second evaporator, said means including a bypass conduit connected to the receiver above any liquid level therein and to the first conduit at 'a point in advance of the suction side of the compressor to bypass the condenser serving as a second evaporator when reverse flow is taking place, a valve seat and valve member controlling flow through the bypass conduit, said valve member urged toward its seat by a plunger, a pressure responsive member secured to the plunger and reciprocating the plunger upon movement thereof, said pressure responsive member exposed on one side to pressure fluid in the first conduit whereby movement of the pressure responsive member is influenced by suction pressure and the diiferential between suction pressure and receiver pressure is regulated in response to changes in a condition of the refrigerant generated by the second evaporator during reverse cycle operation.

12.In a refrigerating system comprising, means ineluding a discharge line connecting the high side of a compressor to a condenser, means including a suction line connecting the low side of the compressor to an evaporator, a first liquid line connecting a liquid receiver to said evaporator for conducting liquid refrigerant from the receiver to the evaporator, a second liquid line connecting the receiver to the condenser for conducting liquefied refrigerant from the condenser to the receiver and for conducting liquid refrigerant from the receiver to the condenser whenever the receiver pressure exceeds the condenser pressure, a bypass conduit by-passing said second liquid line and connecting the receiver and the said discharge line, and flow control means for changing the rel- .ative pressures in the receiver and the condenser to cause liquid refrigerant to flow from the receiver to the condenser through said second liquid line.

'13. The refrigerating system of claim 12 wherein said flow control means comprises a pressure regulating valve for controlling flow through said by-pass conduit to thereby control receiver pressure and the flow of liquid refrigerant from the receiver to the condenser.

14. The refrigerating system of claim 12 wherein said flow control means comprises means to reverse the flow of refrigerant through said system.

15. The refrigerating system of claim 12 wherein the said flow control means comprises means to reverse the how of refrigerant in said system and to control receiver pressure after said flow has been reversed.

16. In a refrigeration system comprising, a heat exchanger for condensing a refrigerant, a heat exchanger for evaporating a refrigerant, a compressor for circulating refrigerant, a vessel for receiving and storing liquefied refrigerant inter-connected between the two said heat'exchangers, liquid transfer means for transferring liquid refrigerant from said vessel to at least one of said heat exchangers, means for connecting said vessel to the low side of the compressor for transferring refrigerant from the said vessel to the low side of the compressor without passing through either of said heat exchangers, and means for controlling the flow of refrigerant from said vessel to the low side of the compressor through said means.

17. In a refrigeration system comprising, a compressor with its low side connected to an evaporator and its high side connected to a first condenser, and the discharge of the first condenser connected through a liquid receiver to the evaporator to provide a refrigerating circuit, means for reversing the flow of refrigerant in said circuit to convert the evaporator to a second condenser and the first condenser to a second evaporator, means connecting the receiver, the second evaporator, and the compressor for transferring liquefied refrigerant from the receiver to said second evaporator and for transferring gaseous refrigerant from the receiver and the second evaporator to the low side of the compressor, and flow control means operable in response to changes of a variable condition of the refrigerant in said circuit for regulating the rate of flow of liquid refrigerant from the receiver to said second evaporator and the rate of flow of gaseous refrigerant from the receiver and the second evaporator to the low side of the compressor.

18. In refrigeration apparatus, in combination, a heat exchanger for exchanging heat between refrigerant and another fluid, a first opening in said heat exchanger for admitting or releasing gaseous refrigerant to or from said heat exchanger, a second opening in said heat exchanger for admitting or releasing liquefied refrigerant to or from said heat exchanger, a vessel for receiving and storing liquid refrigerant, liquid transfer means connecting said vessel and the said second opening in the heat exchanger for transferring liquefied refrigerant from the vessel to the heat exchanger or from the heat exchanger to the vesesl, a conduit connected to said first opening for conducting gaseous refrigerant to or from said heat exchanger, and means including a flow control valve con- ,necting said conduit and said vessel and lay-passing said liquid transfer means for conducting gaseous refrigerant between said vessel and said conduit without passing through said liquid transfer means, said flow control valve being operable in response to a condition of the refrigenant in said apparatus for controlling a condition of said refrigerant.

19. In refrigeration apparatus including a compressor for circulating a refrigerant, in combination, a heat exchanger for exchanging heat between a refrigerant and other substance, a vessel for storing liquid refrigerant, means connecting the vessel and the heat exchanger providing an unrestricted path of flow for transferring liquid refrigerant from the vessel to the heat exchanger, and means operable in response to a condition of said refrigerant to establish and maintain a pressure differential between the pressure of the refrigerant in the vessel and the pressure of the refrigerant in the heat exchanger equal to the pressure required to transfer liquid refrigerant through said unrestricted path'of flow from the vessel .to the heat exchanger rat a rate proportionate to the re- .quirements of the heat exchanger'for producing said condition.

20. In a refrigeration system including a compressor for circulating a refrigerant, heat exchangers for exchanging heat between the refrigerant and other substance, and means to reverse the flow of refrigerant through a fluid circuit of said system .to alternately heat and cool at least one of said heat exchangers, a vessel for receiving and storing liquid refrigerant connected in said circuit between the heat exchangers, liquid transfer means connecting the vessel and at least one of said heat exchangers for transferring liquid refrigerant from the vessel to said one of said heat exchangers, means connecting the vessel and the low side of the compressor for transferring gaseous refrigerant from said vessel to the low side of the compressor when the flow of liquid refrigerant in said circuit is directed from the vessel to the said one of said heat exchangers, and means operable in response to a condition of the refrigerant in said circuit for controlling the flow of gaseous refrigerant from the vessel to the low side of the compressor to establish and maintain a pressure differential between the pressure of-the refrigerant in the vessel and the pressure of the refrigerant in the said one of said heat exchangers to which the liquid refrigerant is transferred, at least equal, to the pressure required to transfer liquid refrigerant from the vessel to said one :of said heat exchangers at a rate proportionate to the requirements of the latter heat exchanger for producing said condition.

21. In a refrigeration system, a compressor for circulating a refrigerant, at least two heat exchangers connected to the compressor for evaporating and condensing refrigerant, means for alternately connecting each of said heat exchangers to the discharge and suction sides of the compressor to alternately change the function of each from condensing to evaporating or from evaporating to condensing refrigerant, a vessel connected between said heat exchangers for storing liquefied refrigerant for supplying liquid refrigerant to at least one of said heat exchangers when the latter heat exchanger is connected to the suction side of the compressor, means for transferring iliquid refrigerant from said vessel to said one of said heat exchangers and for transferring gaseous refrigerant from said vessel. to the suction side of the compressor when said one of said heat exchangers is connected thereto, means regulating flow of gaseous refrigerant through said transfer means including a pressure regulating valve inter-connected in said transfer means for controlling the flow of gaseous refrigerant to the compressor, said regulating valve regulating the flow of gaseous refrigerant to the compressor when said one of said heat exchangers is connected to the suction side of the compressor, and means providing substantially unrestricted flow from the com- 13 pressor to said one of said heat exchangers when the latter is connected to the compressor discharge.

22. In refrigeration apparatus interconnected between the discharge and suction ports of a compressor comprising, a heat exchanger for condensing a refrigerant, an evaporator for evaporating refrigerant, means connecting the said heat exchanger, evaporator, and compressor, providing a circuit for the fiow of refrigerant between said discharge and suction ports of the compressor, a pressure vessel interconnected between the outlet of the said heat exchanger and the inlet of the evaporator for receiving and discharging condensed refrigerant, means connecting said pressure vessel and the suction side of the compressor for transferring gaseous refrigerant to the compressor from said pressure vessel to cause evaporation of condensed refrigerant received thereby, means connecting the evaporator and the suction side of the compressor for transferring gaseous refrigerant to the compressor from the evaporator to cause evaporation of liquid refrigerant transferred thereto from said pressure vessel, and rneans for controlling the evaporating pressure of the refrigerant in said pressure vessel to provide a difference of pressure between the pressure vessel and the evaporator to effect liquid flow from said vessel to the evaporator.

23. An apparatus for use in the operation of heat pumps and reversible refrigerating apparatus for heating and cooling comprising, a compressor having an inlet for receiving refrigerant at a low pressure and an outlet for discharging the refrigerant at a higher pressure, means for condensing a refrigerant to reject heat from said apparatus, a second means for evaporating a refrigerant to absorb heat from a heat source, means interconnecting said first and second means between the inlet and outlet of said compressor providing a flow circuit for refrigerant between said outlet and said inlet, means for removing a portion of the refrigerant circulating in said circuit from circulation therein at a point between the compressor outlet and the inlet of said second means, means for conditioning said portion of refrigerant for transfer to the inlet of the compressor, means for returning that portion of the refrigerant removed from said circuit and transferring it to the inlet of the compressor after it has been conditioned for transfer thereto, and means for controlling the amount of refrigerant removed from and returned to said circuit.

24. An apparatus for use in the operation of heat pumps and reversible refrigerating apparatus for heating and cooling comprising, a compressor having an inlet for receiving refrigerant at a low pressure and an outlet for discharging the refrigerant at a higher pressure, means for condensing a refrigerant to reject heat from said apparatus, a second means for evaporating a refrigerant to absorb heat from a heat source, means interconnecting said first and second means between the inlet and outlet of said compressor providing a flow circuit for refrigerant between said outlet and said inlet, means for with-drawing a portion of the refrigerant from said circuit between the outlet of compressor and inlet to the evaporator, means for cooling by refrigerating process said portion of the refrigerant which is withdrawn, means for passing the cooled refrigerant to the low side of said compressor, and means for controlling the amount of the refrigerant withdrawn and passed in the cooled state to the low side of said compressor.

25. An apparatus for use in the operation of heat pumps and reversible refrigerating apparatus for heating and cooling comprising, a compressor having an inlet for receiving refrigerant at a low pressure and an outlet for discharging the refrigerant at a higher pressure, means for condensing a refrigerant to reject heat from said apparatus, a second means for evaporating a refrigerant to absorb heat from a heat source, means interconnecting said first and second means between the inlet and outlet of said compressor providing a flow circuit for refrigerant between said outlet and said inlet, a third means in said circuit for cooling the refrigerant by a refrigerating process, means for evaporating a portion of said refrigerant in said circuit in said third means to render it gaseous and to withdraw such portion from said circuit for preventing such withdrawn portion from serving as an effective refrigerant in said second means, and means for passing said gaseous refrigerant from said third means to the low side of said compressor, means for controlling the amount of gaseous refrigerant passing to said low side of said compressor from said third means to thereby control the amount of refrigerant evaporated in said second means.

26. In refrigerating apparatus useful in the operation of heat pumps and other refrigerating systems of the character described, a refrigerant for circulation in said apparatus, a compressor for circulating said refrigerant, a circuit for the flow of refrigerant including at least two heat exchanges connected between the inlet and outlet of said compressor for transferring heat between refrigerant and other heat transferring mediums, flow reversing means for changing the direction of flow of refrigerant through said heat exchangers to thereby change the direction of the flow of heat transferred therefrom, one of said heat exchangers being adapted to transfer heat between refrigerant and water, conduit means for conducting a flow of water into indirect heat exchange relation with the refrigerant circulating in said one heat exchanger, and at least two flow control valves operable jointly for controlling said flow of water through said conduit means in response to conditions of said refrigerant in said circuit.

27. In refrigerating apparatus useful in the operation of heat pumps and other related refrigeration systems of the character described, a refrigerant for circulation in said apparatus, a compressor for circulating said refrigerant, a first flow circuit for conducting refrigerant from the outlet to the inlet of said compressor and including at least two heat exchangers for condensing and evaporating refrigerant connected between the outlet and the inlet of said compressor, a second flow circuit for conducting refrigerant from said outlet to said inlet of the compressor, said second flow circuit including a part of said first flow circuit and bypass means bypassing another part thereof, said bypass means being connected between the outlet and the inlet of said compressor for conducting a portion of the refrigerant circulating in said apparatus from the outlet to the inlet of said compressor without passing through said other part of said first flow circuit to thereby reduce the pressure and the flow of refrigerant in said first flow circuit, said second flow circuit also including means for vaporizing refrigerant to thereby condition the refrigerant passed through said bypass means for compression by the compressor before it is transmitted thereto through said inlet, and means for regulating the flow of refrigerant through said bypass means.

28. In refrigeration apparatus useful in the operation of heat pumps and other refrigerating systems of the character described, at least two heat exchangers for transferring heat between refrigerant and other heat transferring mediums, a refrigerant for circulation in said apparatus, a compressor for compressing gaseous refrigerant to cause said circulation, a pressure vessel for accumulating and withholding at least a portion of said refrigerant from circulation in said apparatus, means for reducing the pressure in said vessel to cause a portion of said refrigerant to be accumulated and withheld from circulation in said apparatus, means for increasing the pressure in said vessel after said reducing of pressure has caused accumulation of refrigerant therein to thereby cause at least a portion of the refrigerant accumulated in said vessel to flow back into circulation in said apparatus, and means for controlling said reducing and said increasing of pressure in said pressure vessel to thereby control the amount of refrigerant circulating in said apparatus.

29. In refrigerating apparatus useful in the operation of heat pumps and other related refrigeration systems of the character described, a compressor for circulating a ducting fiow of refrigerant from the outlet to the inlet connected to the outlet of the compressor for condensing refrigerant, a second heat exchanger means connected to the inlet of the compressor for evaporating refrigerant, and means connecting the outlet of the first heat exchanger means with the inlet of the second heat exchanger means for conducting flow of refrigerant therebetween, a'second flow circuit for conducting flow of refrigerant from the outlet to the inlet of said compressor including a part of said first flow circuit and bypass means bypassing another part thereof for conducting a part of the refrigerant circulated by said compressor from the outlet to the inlet of said compressor without passing through a part of said first flow circuit to thereby influence the flow of refrigerant through said first flow circuit, saidsecond flow circuit including means for evaporating refrigerant for transfer to the inlet of the compressor, and means for regulating the flow of refrigerant through the bypass means of the said second flow .of said compressor including, a first heat exchanger means circuit to thereby control the degree of said influence on the flow of refrigerant through said first flow circuit.

30. In refrigeration apparatus operable to conduct and control circulation of refrigerant from the outlet to the inlet of a compressor in the operation of said apparatus to transfer heat, a receptacle for containing a part of the refrigerant in said apparatus while another part of said refrigerant is circulating therein, and means operable to regulate the flow of said refrigerant down stream from said receptacle during at least a part of said operation of said apparatus including flow regulating means connected down stream from said receptacle for controlling the transfer of refrigerant from said receptacle during at least said part of said operation, said flow regulating means including a flow regulating valve adapted for movement in a direction away from its closed position by pressure of the refrigerant contained in said receptaclc.

References Cited in the file of this patent UNITED STATES PATENTS 2,446,910 Dickens Aug. 10, 1948 2,710,507 Ashley June 14, 1955 2,878,654 Kramer Mar. 24, 1959 

30. IN REFRIGERATION APPARTUS OPERABLE TO CONDUCT AND CONTROL CIRCULATION OF REFRIGERANT FRON THE OUTLET TO THE INLET OF A COMPRESSOR IN THE OPERATION OF SAID APPARATUS TO TRANSFER HEAT, A RECEPTACLE FOR CONTAINING A PART OF THE REFRIGERANT IN SAID APPARATUS WHILE ANOTHER PART OF SAID REFRIGERANT IS CIRCULATING THEREIN, AND MEANS OPERABLE TO REGULATE THE FLOW OF SAID REFRIGERANT DOWM STREAM FROM SAID RECEPTACLE DURING AT LEAST A PART OF SAID OPERATION OF SAID APPARATUS INCLUDING FLOW REGULATING MEANS CONNECTED DOWN STREAM FROM SAID RECEPTACLE FOR CONTROLLING THE TRANSFER OF REFRIGERANT FROM SAID RECEPTACLE DURING AT LEAST SAID PART OF SAID OPERATION, SAID FLOW REGULATING MEANS INCLUDING A FLOW REGULATING VALVE ADAPTED FOR MOVEMENT IN A DIRECTION AWAY FROM ITS CLOSED POSITION BY PRESSURE OF THE REFRIGERANT CONTAINED IN SAID RECEPTACLE. 